Calc II Partial Fractions with Natural Logs

Click For Summary

Homework Help Overview

The problem involves evaluating the integral \(\int\frac{dx}{x(1+\ln x)}\), which raises questions about the appropriate methods for integration, particularly the use of partial fractions.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply partial fractions but expresses confusion about the method's applicability to the integrand. Some participants suggest alternative approaches, including substitutions involving logarithmic functions.

Discussion Status

Participants are exploring different methods for solving the integral, with some questioning the validity of using partial fractions for the given function. A substitution has been proposed as a potential alternative, indicating a productive direction in the discussion.

Contextual Notes

There is a noted difficulty in understanding partial fractions, and the original poster seeks clarification on the reasoning behind the suggested methods. The discussion reflects uncertainty about the correct approach to the integral.

demersal
Messages
41
Reaction score
0

Homework Statement



[tex]\int[/tex][tex]\frac{dx}{x(1+ln x)}[/tex]

Homework Equations


Partial Fractions? Maybe I am solving this wrong...


The Attempt at a Solution



[tex]\frac{A}{X}[/tex] + [tex]\frac{B}{1+ln x}[/tex] = 1

A(1+lnx) + Bx =1
A + Alnx + Bx =1

This doesn't seem to work out properly. I have been having a lot of trouble understanding partial fractions so any help in assisting me in making this first step of the problem would be greatly appreciated! Even if partial fractions aren't the correct way to go about this, if you could explain how you knew what to do, I think it would help me a lot in the long run! Thanks!
 
Physics news on Phys.org
I don't think you can use partial fractions like that since the integrand is not a rational function.

Try a substitution, let u=1+ln x
 
let u=lnx
 
ignore me! i was sick :(
 
rocomath said:
ignore me! i was sick :(

Your sub still works too
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
2K
Replies
9
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K